A. c. contactor with d. c. magnet construction



Feb. 25, 1958 v. G. KRENKE 2,825,013

A. C. CONTACTOR WITH D. MAGNET CONSTRUCTION Filed May 11, 1955 I; Flg. l. i d: l 1' x i @9 6 mwumml m I 5 T! .5 @119 i I 1:1; I 05 x if c ig fl\ s I C t) fliu-un- M I C I I11 1 imltflflb WITNESSES INVENTOR Vincent 6. Krenke. MJFZW ATTORNEY United States Patent fiic e 2,825,013 Patented eb. 25, 1958 A. C. CONTACTOR WITH D. C. MAGNET CONSTRUCTION Vincent G. Krenke, Granger, Ind., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application May 11, 1955, Serial No. 507,597 12 Claims. cl. 317-165) The invention relates to electromagnetically actuated contactors and more particularly to electromagnetically actuated contactors for use with direct current.

The design and construction of alternating current magnetic-contactors has attained a high degree of utility and elficiency, but direct current actuated contactors' have received less attention from inventors and engineers so that the direct current contactors are usually larger for the same rating and thus cost more, and above all have a much lesser advantageous space factor.

One broad object of my invention is the provision of a direct current actuated contactor having the same physical size as an alternating current contactor of like rating.

Another broad object of my invention is an improvement and relatively simple reconstruction of an alternating current contactor to make the contactor an efiicient direct current contactor.

A further object of my invention is to provide soft iron non-laminated operating mechanisms in which the solid actuating armature is positioned between the solid magnet core and its solid iron supporting structure and in which the solid iron supporting structure forms part of the magnetic circuit. I

A specific object of my invention is the provision of a solid iron supporting structure for a movable armature so designed in relation to the movable armature that the air gap remains small and relatively constant in relation to the movable armature regardless of the position of the armature within the range of its movement with reference to a solid iron core also supported on the supporting structure.

The objects recited are merely illustrative. Other ob jects and advantages will become more apparent from a study of the following specification and the accompanying drawing, in which:

Figure 1 is a side view of my contactor with some parts broken away to show some details; and

Fig. 2 is a side view of the essential elements of my contribution to the art with the armature shown slightly schematic.

Referring to the drawing, the switch illustrated in Fig. l is a line-starter type particularly adapted for connecting an electric motor or other load across the leads of a source of an electric power supply. The main parts of the switch comprise an electromagnet M, a bracket member B, mounted in spacedrelation with respect to the support S, and having an armature A connected to its lower end, a movable contact carrying cross bar CB connected to its upper end, and a pivot structure for the armature intermediate the lower end and the cross bar CB. The structural features of the parts M, S, B, A and CB, and certain other parts associated with these parts and discussed below, and the manner in which the parts cooperate are such as to provide a switch which is smaller and more compact for a given rating and capacity than prior art constructions, contain a minimum of relatively movable parts subject to wear and likely to become out of order, and in which the parts may be readily taken 2 apart for inspection and repair. In a sense, the contribution 1' have made is an improvement and redesign of the contactor disclosed in the D. Ellis Patent No. 2,550,- 110. L utilize the same frame sizes, contact components, and chute, etc. to provide a direct'current contactor havmg). rating and capacity as the same irame size for alterhating current seryice.

The support]. includes a base member adapted to be secured to a panelboard, or in a cabinet, and is preferably mounted in a vertical position as shown in Fig. l. The three main other elements of the support comprise the brackets 2 and 3 and the front plate 4. The contact arrangements, the arc chamber 5, the auxiliary contact assembly 6, etc., are all conventional and well known, as indicated in the patent mentioned. No detailed description need, thererore, be given.

The electromagnet includes the coil C and the magnetic circuit. 'lne magnetic circuit comprises the base 1 chosen or sohd iron, not too hard, and or good magnetic characteristics, to which the brackets 2 and 3 are tirmly bolted, as shown in Pig. 1, so as to provide the very minimum or reiuctanceacross the bolted joints. The brackets, similar to base 1, are also solid iron, i. e., not laminated, and are also or metal, not too hard, and chosen to have good magnetic characterlstics. The rront plate 4 is also chosen or the same type of iron of good magnetic characteristics and is sohd and is bolted to the right-hand ends of the brackets 2 and 3. A solid soft iron core CU is intimately secured to the rear surrace of the front plate so as to have a low reluctance connection with the'front plate 4.

The armature A at its upper end extends through an opening 5 in the bracket 2, the opening having such a transverse width that the air gaps at the edges of the armature are very small but not so small as to bind the movement of the armature in its arcuatc movement about pivot P. The armature is also solid and chosen of iron having good magnetic characteristics.

It will be noted that the bracket 3 for the major portion of its length is disposed at right angles to the front plate 4, but at its rear end from point 7 to point 8 the bracket curves upward so as to provide a very small air gap between the lower end of the armature and the bracket 3 for the entire arcuate movement of the armature. 'lhis air gap is kept at from 0.10 to no more than .015 of an inch. This small air gap provides for a low reluctance path where low reluctance is needed. The gap is neverthcless suniciehtly large to prevent any binding between the armature and the bracket 3.

When the coil is energized, the magnetic flux flows as indicated by the arrows and thus pulls the armature in a counterclockwise direction against the left-hand end of core CO. The various contacts are thus operated by the movement of the armature. The bracket B is rigidly secured to the armature and has outwardly projecting arms to engage the bracket 2 to make certain that pivot point P is always against the bracket 2.

Item 10 is a stop of insulating material that is also nonmagnetic. The main importance is that it be non-magnetic. Since insulating material, except some special insulating material that has recently been developed, is usually non-magnetic, an easy choice of material can; of course, be made.

A nonmagnetic shim 11 is also brazed to the rear end of the core C0 to assure dropout of the contactor at a proper reduced voltage on the coil C. Item 12 is also of non-magnetic material and prevents the coil C from in any way moving out of position. The coil core C is preterably shaped square in section or has some other polygonal transverse section to prevent the coil from turning on the core.

While I have shown and described but one embodiment loop including the core,

3 of my invention, it is to be understood that the invention is capable of various adaptations and that changes and modifications may be made that-all fall within the spirit and scope of my invention.

"I claim as my invention:

1. In an electromagnetically operable contactor, in combination, a base, a solid metal element of good magnetic characteristics secured to the base and projecting from the base, a solid metal armature of substantially the same magnetic characteristics pivoted on the element near the connection of the element to tligbase and depending for arcuate movement from the element, a second similar solid metal element secured to the base and projecting in the same direction from the base, said second element being disposed adjacent to the lower end of the depending armature, a solid metal connecting member of good mag netic characteristics secured to the free ends of the two elements, a solid metal coil supporting core of good magnetic characteristics secured to the connecting member between the two elements, said core projecting toward the depending armature, and a magnetizing coil on the core, whereby energization of the coil magnetizes the armature, the two elements, and the connecting member in two magnetic loops, one loop including the core, the upper portion of the armature, the upper element, and the upper portion of the connecting member, and the second the lower portion of the armature, the lower element, and the lower portion of the connecting member.

2. In an electromagnetically operable contractor, in combination, a base, a solid metal element of good magnetic characteristics secured to the base and proiecting from the base, a solid metal armature of substantially the same magnetic characteristics pivoted on the element near the connection of the element to the base and depend ng for arcuate movement from the element, a second similar solid metal element secured to the base and projecting in the same direction from the base, said second element being disposed adjacent to the lower end of the depending armature with aportion of the second element being bent to substantially conform to the arcuate movement of the lower end ofthe armature to thus provide a small air gap between the second element and lower end of the armature during arcuate movement of the armature, a solid metal connecting member of good magnetic characteris'tics secured to the free ends of the two elements, a solid metal coil su porting core of good magnetic characterlSlJCS secured to the connecting member between the two elements. said core projecting toward the depending armature, and a magnetizing coil on the core, whereby energization of the coil magnetizes the armature, the two elements, and the connecting member in two magnetic loops. one loop including the core, the upper portion of the armature, the upper element. and the up er portion of the connecting member, .and the second loop including the core, the lower portion of the armature, the lower element, and the lower portion of the connecting member.

3 In an electromagnetically operable contactor, in combination, a base, a first solid metal element secured at one end to the base and projecting to the right from the base, a solid metal armature pivoted on the element so as to depend for arcuate movement over a selected range from the element, a second solid metal element secured to the base and projecting to the right from the base, the disposition of the second element being such that it is near the lower end of the depending armature, a solid metal connecting member secured to the free ends of the elements, a solid metal coil supporting core secured to the connecting member and projecting to the left so that the free end of the core is in operative relation to the armature, said elements, armature, connecting member, and .core being chosen of ametal having good magnetic characteristics, and a magnetizing coil on the core, where by energization of the coil with direct current magnetizes the armature, the two elements, the core, and the connecting member in two loops, one loop including the core, the upper portion of the armature, the first element, the upper portion of the connecting member and the second loop including the core, the lower portion of the armature, the second element and the lower portion of the connecting member.

4. In an electromagnetically operable contactor, in combination, a base, a first solid metal element secured at one end to the base and projecting to the right from the base, a solid metal armature pivoted on the element so as to depend for arcuate movement over a selected range from the element, a second solid metal element secured to the base and projecting to the right from the base, the disposition of the second element being such that it is near the lower end of the depending armature with a portion of the second element being bent to substantially conform to the arcuate movement of the lower end of the armature to thus provide a relatively small air gap between the second element and the lower end of the armature during .arcuate movement of the armature over its selected range, a solid metal connecting member secured to the free ends of the elements, a solid metal coil supporting core secured to the connecting member and projecting to the left so that the free end of the. core is in operative relation to the armature, said elements, armature, connecting member, and core being chosen of a metal having good magnetic characteristics, and a magnetizing coil on the core, whereby energization of the coil withdirect current magnetizes the armature, the two elements, the core and the connecting member in two loops, one loop including the core, the upper portion of the armature, the first element, the upper portion of the connecting member and the second loop including the core, the lower portion of the armature, the second element and the lower portion of the connecting member.

5. In an electromagnetically operable contactor, in combination, a plate-like base, a strap-like element at one end secured to the base and disposed to project to the right substantially at right angles from the base, said element having a rectangular opening therethrough near the connection of the element to the base, an L-shaped armature having a short leg and a longer leg, said armature having its shorter leg and adjacent portions of the larger leg projecting through the opening in the element with the short leg pivoting on the'upper surface of the element and the edges of the armature being disposed in close proximity to the internal edges of the opening whereby an air gap of minimum dimensions is main tained between the armature and element, said armature thus depending from the element for arcuate movement over a selected range, a second strap-like element at one end secured to the base and disposed to project to the right substantially at right angles from the base, the disposition of the second element being such that it is near the lower end of the longer leg of the depending armature, a strap-like connecting member secured to the free ends of the elements, a coil supporting core secured to the connecting member and projecting to the left at substantially right angles to the member to thus be substantially parallel to the elements with the left end of the core being disposed in operative relation to the armature, said elements, armature, connecting member, and core being chosen of solid metal having good magnetic characteristics to provide a contactor of service for dircet current magnetization, and a magnetizing coil on the core, whereby energization of the coil with direct current magnetizes the armature, the two elements, the core, andconnecting member in two loops, one loop including the core, the upper portion of the armature,the first, or upper, element, and the upper portion of the connecting member and the lower loop including the core, the lower portion of the armature, the second, or lower, element, and the lower portion of the connecting member.

6. In an electromagnetically operable contactor, in

combination, a plate-like base, a strap-like element at one end secured to the base and disposed to project to the right substantially at right angles from the base, said element having a rectangular opening therethrough near the connection of the element to the base, an L-shaped armature having a short leg and a longer leg, said armature having its shorter leg and adjacent portions of the longer leg projecting through the opening in the element with the short leg pivoting on the upper surface of the element and the edges of the armature being disposed in close proximity to the internal edges of the opening whereby an air gap of minimum dimensions is maintained between the armature and element, said armature thus depending from the element for arcuate movement over a selected range, a second strap-like element at one end secured to the base and disposed to project to the right substantially at right angles from the base, the disposition of the second element being such that it is near the lower end of the longer leg of the depending armature with a portion of the second element being bent to substantially conform to the arcuate movement of the lower end of the longer leg of the armature to thus provide a relatively small air gap between the second element and the lower end of the longer leg of the armature during arcuate movement of the armature over its selected range, a straplike connecting member secured to the free ends of the elements, a coil supporting core secured to the connecting member and projecting to the left at substantially right angles to the member to thus be substantially parallel to the elements with the left end of the core being disposed in operative relation to the armature, said elements, armature, connecting member, and core being chosen of solid metal having good magnetic characteristics to provide a contactor of service for direct current magnetization, and a magnetizing coil on the core, whereby energization of the coil with direct current magnetizes the armature, the two elements, the core, and connecting member in two loops, one loop including the core, the upper portion of the armature, the first, or upper, element, and the upper portion of the connecting member and the lower loop including the core, the lower portion of the armature, the second, or lower, element, and the lower portion of the connecting member.

7. In an electromagnetically operable contactor, in combination, a plate-like base, a strap-like element at one endsecured to the base and disposed to project to the right substantially at right angles from the base, said element having a rectangular opening therethrough near the connection of the element to the base, an L-shaped armature having a short leg and a longer leg, said armature having its shorter leg and adjacent portions of the larger leg projecting through the opening in the element with the short leg pivoting on the upper surface of the element and the edges of the armature being disposed in close proximity to the internal edges of the opening whereby an air gap of minimum dimensions is maintained between the armature and element, said armature thus depending from the element for arcuate movement over a selected range, a second strap-like element at one end secured to the base and disposed to project to the right substantially at right angles from the base, the disposition of the second element being such that it is near the lower end of the longer leg of the depending armature, a straplike connecting member secured to the free ends of the elements, a coil supporting core secured to the connecting member and projecting to the left at substantially right angles to the member to thus be substantially parallel to the elements with the left end of the core being disposed in operative relation to the armature, said elements, armature, connecting member, and core being chosen of solid metal having good magnetic characteristics to provide a contactor of service for direct current magnetization, a stop on the base opposite the left end of the core to limit the arcuate movement of the supra ture to a selected range, and a magnetizing coil on the core, whereby energization of the coil with direct current magnetizes the armature, the two elements, the core, and connecting member in two loops, one loop including the core, the upper portion of the armature, the first, or upper, element, and the upper portion of the connecting member and the lower loop including the core, the lower portion of the armature, the second, or lower, element, and the lower portion of the connecting member.

8. In an electromagnetically operable contactor, in combination, a plate-like base, a strap-like element at one end secured to the base and disposed to project to the right substantially at right angles from the base, said element having a rectangular opening therethrough near the connection of the element to the base, an L-shaped armature having a short leg and a longer leg, said armature having its shorter leg and adjacent portions of the larger leg projecting through the opening in the element with the short leg pivoting on the upper surface of the element and the edges of the armature being disposed in close proximity to the internal edges of the opening whereby an air gap of minimum dimensions is maintained between the armature and element, said armature thus depending from the element for arcuat-e movement over a selected range, a second strap-like element at one end secured to the base and disposed to project to the right substantially at right angles from the base, the disposition of the second element being such that it is near the lower end of the longer leg of the depending armature, a straplike connecting member secured to the free ends of the elements, a coil supporting core secured to the connecting member and projecting to the left at substantially right angles to the member to thus be substantially parallel to the elements with the left end of the core being disposed in operative relation to the armature, said elements, armature, connecting member, and core being chosen of solid metal having good magnetic characteristics to provide a contactor of service for direct current magnetization, a non-magnetic shim on the left end of the core to assure drop-out of the contactor after deenergization, and a magnetizing coil on the core, whereby energization of the coil with direct current magnetizes the armature, the two elements, the core, and connecting member in two loops, one loop including the core, the upper portion of the armature, the first, or upper, element, and the upper portion of the connecting member and the lower loop including the core, the lower portion of the armature, the second, or lower, element, and the lower portion of the connecting member.

9. In an electromagnetically operable contactor, in combination, a plate-like base, a strap-like element at one end secured to the base and disposed to project to the right substantially at right angles from the base, said element having a rectangular opening therethrough near the connection of the element to the base, an L- shaped armature having a short leg and a longer leg, said armature having its shorter leg and adjacent portions of the longer leg projecting through the opening in the element with the short leg pivoting on the upper surface of the element and the edges of the armature being disposed in close proximity to the internal edges of the opening whereby an air gap of minimum dimensions is maintained between the armature and element, said armature thus depending from the element for arcuate movement over a selected range, a second strap-like element at one end secured to the base and disposed to project to the right substantially at right angles from the base, the disposition of the second element being such that it is near the lower end of the longer leg of the depending armature wiht a portion of the second element being bent to substantially conform to the armate movement of the lower end of the longer leg of the armature to thus provide a relatively small air gap between the second element and the lower end of the longer leg of the armature during arcuate movement of the armature over its selected range. a strap-like connecting member secured to the free ends of the elements, a coil supporting core secured to the connecting member and projecting to the left at substantially right angles to the member to thus be substantially parallel to the elements with the left end of the core being disposed in operative relation to the armature, said elements, armature, connecting member, and core being chosen of solid metal having good magnetic characteristics to provide a contactor of service for direct current magnetization, a stop on the base opposite the left end of the core to limit the arcuate movement of the armature to a selected range, and a magnetizing coil on the core, whereby energization of the coil with direct current magnetizes the armature, the two elements, the core, and connecting member in two loops, one loop including the core, the upper portion of the armature, the first, or upper, element, and the upper portion of the connecting member and the lower loop including the core, the lower portion of the armature, the second, or lower, element, and the lower portion of the connecting member.

10. In an electromagnetically operable contactor, in combination, a plate-like base, a strap-like element at one end secured to the base and disposed to project to the right substantially at right angles from the base, said element having a rectangular opening therethrough near the connection of the element to the base, an L-shaped armature having a short leg and a longer leg, said armature having its shorter leg and adjacent portions of the longer leg projecting through the opening in the element with the short leg pivoting on the upper surface of the element and the edges of the armature being disposed in close proximity to the internal edges ofthe opening whereby an air gap of minimum dimensions is maintained between the armature and element, said armature thus depending from the element for arcuate movement over a selected range, a second strap-like element at one end secured to the base and disposed to project to the right substantially at right angles from the base, the disposition of the second element being such that it is near the lower end of the longer leg of the depending armature with a portion of the second element being bent to substantially conform to the arcuate movement of the lower end of the longer leg of the armature to thus provide a relatively small air gap between the second element and the lower end of the longer leg of the armature during arcuate movement of the armature over its selected range, a strap-like connecting member secured to the free ends of the elements, a coil supporting core secured to the connecting member and projecting to the left at substantially right angles to the member to thus be substantially parallel to the elements with the left end of the core being disposed in operative relation to the armature, said elements, armature, connecting member, and core being chosen of solid metal having good magnetic characteristics to provide a contactor of service for direct current magnetization, a non-magnetic shim on the left end of the core to assure drop-out of the contactor after deenergization, and a magnetizing coil on the core, whereby energization of the coil with direct current magnetizes the armature, the two elements, the core, and connecting member in two loops, one loop including the core, the upper portion of the armature, the first, or upper, element, and the upper portion of the connecting member and the lower loop including the core, the lower portion of the armature, the second, or lower, element, and the lower portion of the connecting member.

ll. In an electromagnetically operable contactor, in combination, a plate-like base, a strap-like element at one end secured to the base and disposed to project to the right substantially at right angles from the base, said element having a rectangular opening therethrough near the connection of the element to the base, an L-shaped armature having a short leg and a longer leg, saidarmature having its shorter leg and adjacent portions of the longer leg projecting through the opening in the element with the short leg pivoting on the upper surface of the element and the edges of the armature being disposed in close proximity to the internal edges of the opening whereby an air gap of minimum dimensions is maintained between the armature and element, said armature thus depending from the element for arcuate movement over a selected range, a second strap-like element at one end secured to the base and disposed to project to the right substantially at right angles from the base, the disposition of the second element being such that it is near the lower end of the longer leg of the depending armature with a portion of the second element being bent to substantially conform to the arcuate movement of the lower and of the longer leg of the armature to thus provide a ratively small air gap between the second element and the lower end of the longer leg of the armature du 1g arcuate movement of the armature over its selected range, a strap-like connecting member secured to the free ends of the elements, a coil supporting core secured to the connecting member and projecting to the left at substantially right angles to the member to thus be substantially parallel to the elements with the left end of the core being disposed in operative relation to the armature, said elements, armature, connecting member, and core being chosen of solid metal having good magnetic characteristics to provide a contactor of service for direct current magnetization, a stop on the base opposite the left end of the core to limit the arcuate movement of the armature to a selected range, a non-magnetic shim on the left end of the core to assure drop-out of the contactor after deenergization, and a magnetizing coil on the core, whereby energization of the coil with direct current magnetizes the armature, the two elements, the core, and connecting member in two loops, one loop including the core, the upper portion of the armature, the first, or upper, element, and the upper portion of the connecting member and the lower loop including the core, the lower portion of the armature, the second, or lower, element, and the lower portion of the connecting member.

12. In an electromagnetically operable contactor, in combination, a plate-like base, a strap-like element at one end secured to the base and disposed to project to the right substantially at right angles from the base, said element having a rectangular opening therethrough' near the connection of the element to the base, an L-shaped armature having a short leg and a longer leg, said armature having its shorter leg and adjacent portions of the longer leg projecting through the opening in the element with the short leg pivoting on the upper surface of the element and the edges of the armature being disposed in close proximity to the internal edges of the opening whereby an air gap of minimum dimensions is maintained between the armature and element, said armature thus depending from the element for arcuate movement over a selected range, a second strap-like element at one end secured to the base and disposed to project to the right substantially at right angles from the base, the disposition of the second element being such that it is near the lower end of the longerleg of the depending armature, a strap-like connecting member secured to the free ends of the elements, a coil supporting core secured to the connecting member and projecting to the left at substantially right angles to the member to thus be substantially parallel to the elements with the left end of the core being disposed in operative relation to the armature, said elements, armature, connecting member, and core being chosen of solid metal having good magnetic characteristics to provide a contactor of service for direct current magnetization, a stop on the base opposite the left end of the core to limit the arcuate movement of the armature to a selected range, a non-magnetic shim on the left end of the core to assure drop-out of the contactor after deenergization, and a magnetizing coil on the core, whereby energization of the coil with direct current mag- 10 netizes the armature, the two elements, the core, and References Cited in the file of this patent connecting member in two loops, one loop including the UNITED STATES PATENTS core, the upper portion of the armature, the first, or

upper, element, and the upper portion of the connecting 1870176 Hodgkins 1932 member and the lower loop including the core, the lower 5 1936779 W 1933 portion of the armature, the second, or lower, element, 2,134,951 Plesker 1938 and the lower portion of the connecting member. 

